Surgical optical zoom system

Abstract

Methods and systems for controlling a surgical microscope. Moveable optics of the surgical microscope are controlled using two sets of control parameters, to reduce jitter and image instability. Shifts in the image due to changes in temperature or due to the use of optical filter can also be compensated. Misalignment between the mechanical axis and the optical axis of the surgical microscope can also be corrected.

The invention claimed is: 
     
       1. An optical camera module comprising:
 an optical assembly including at least one moveable optics; 
 an actuator for positioning the at least one moveable optics, the actuator including a pulley system for moving the at least one moveable optics; 
 a camera for capturing an image from the optical assembly; and 
 an auxiliary optics holding multiple optical filters, the auxiliary optics being positionable to position one of the multiple optical filters in an optical path of the at least one moveable optics; 
 
       wherein the actuator is controlled to:
 position the at least one moveable optics towards a target position using the pulley system that is controlled according to a first set of control parameters when the at least one moveable optics is outside a threshold range of the target position; and 
 maintain the at least one moveable optics at the target position at steady state, using the pulley system that is controlled according to a second set of control parameters when the moveable optics is within the threshold range of the target position. 
 
     
     
       2. The optical camera module of  claim 1 , wherein the multiple selectable optical filters comprise at least one optical filter for fluorescence imaging. 
     
     
       3. The optical camera module of  claim 1 , wherein the multiple optical filters comprise at least one optical filter having a coating that alters the optical path. 
     
     
       4. The optical camera module of  claim 1 , wherein the first and second sets of control parameters are, respectively, first and second sets of proportional (P), integral (I) and derivative (D) terms for dual-PID control of the actuator including the pulley system. 
     
     
       5. The optical camera module of  claim 4 , wherein the second set of control parameters has an I term smaller than the I term of the first set of control parameters by a factor in the range of about 2 to 3. 
     
     
       6. The optical camera module of  claim 1 , further comprising a controller configured to:
 control the actuator to position the at least one moveable optics towards the target position using the pulley system that is controlled according to the first set of control parameters; 
 in response to receiving signals from a sensor detecting that the at least one moveable optics is within the threshold range of the target position, switch to the second set of control parameters to control the actuator to maintain the at least one moveable optics at the target position at steady state using the pulley system that is controlled according to the second set of control parameters. 
 
     
     
       7. The optical camera module of  claim 6 , wherein the controller is further configured to:
 adjust the target position by a compensation amount to compensate for at least one of an optical filter-related optical shift or a temperature-related optical shift; and 
 control the actuator according to the adjusted target position. 
 
     
     
       8. The optical camera module of  claim 7 , wherein the controller is configured to determine the compensation amount using a look-up table or a reference polynomial. 
     
     
       9. The optical camera module of  claim 1 , wherein:
 the at least one moveable optics includes moveable zoom optics and moveable focus optics; 
 the optical camera module comprises at least two actuators including a zoom actuator for positioning the zoom optics and a focus actuator for positioning the focus optics; 
 the zoom actuator and the focus actuator being controlled independently according to first and second sets of zoom control parameters and first and second sets of focus control parameters, respectively. 
 
     
     
       10. The optical camera module of  claim 1 , wherein the optical camera module is configured to be removably mountable to a moveable support structure. 
     
     
       11. The optical camera module of  claim 10 , wherein the moveable support structure is a robotic arm. 
     
     
       12. The optical camera module of  claim 10 , wherein the moveable support structure is a ceiling mounted support. 
     
     
       13. The optical camera module of  claim 1 , for use in a surgical microscope, wherein the at least one moveable optics includes moveable zoom optics and moveable focus optics for capturing a high optical zoom image of a target during a surgical procedure. 
     
     
       14. A method for controlling an optical camera module, the method comprising:
 controlling an actuator including a pulley system to position at least one moveable optics of the optical camera module towards a target position using the pulley system, the pulley system being controlled according to a first set of control parameters, when the at least one moveable optics is outside a threshold range of the target position; 
 controlling the actuator to maintain the at least one moveable optics at the target position at steady state using the pulley system, the pulley system being controlled according to a second set of control parameters, when the at least one moveable optics is within the threshold range of the target position; and 
 controlling an auxiliary optics holding multiple optical filters to position one of the multiple optical filters in an optical path of the at least one moveable optics. 
 
     
     
       15. The method of  claim 14 , wherein the multiple selectable optical filters comprise at least one optical filter for fluorescence imaging, and controlling the auxiliary optics comprises controlling the auxiliary optics to position the at least one optical filter for fluorescence imaging in the optical path. 
     
     
       16. The method of  claim 14 , wherein the first and second sets of control parameters are, respectively, first and second sets of proportional (P), integral (I) and derivative (D) terms for dual-PID control of the actuator including the pulley system. 
     
     
       17. The method of  claim 16 , wherein the second set of control parameters has an I term smaller than the I term of the first set of control parameters by a factor in the range of about 2 to 3. 
     
     
       18. The method of  claim 14 , further comprising:
 adjusting the target position by a compensation amount to compensate for at least one of an optical filter-related optical shift or a temperature-related optical shift; and 
 controlling the actuator according to the adjusted target position. 
 
     
     
       19. The method of  claim 14 , wherein the at least one moveable optics includes moveable zoom optics and moveable focus optics; wherein the actuator comprises at least two actuators including a zoom actuator for positioning the zoom optics and a focus actuator for positioning the focus optics; wherein the first set of control parameters comprises a first set of zoom control parameters and a first set of focus control parameters for controlling the zoom actuator and the focus actuator, respectively; and wherein the second set of control parameters comprises a second set of zoom control parameters and a second set of focus control parameters for controlling the zoom actuator and the focus actuator, respectively. 
     
     
       20. An apparatus comprising:
 a moveable support; and 
 an optical camera module coupled to the moveable support, the optical camera module comprising:
 an optical assembly including at least one moveable optics; 
 an actuator for positioning the at least one moveable optics, the actuator including a pulley system for moving the at least one moveable optics; 
 a camera for capturing an image from the optical assembly; and 
 an auxiliary optics holding multiple optical filters, the auxiliary optics being positionable to position one of the multiple optical filters in an optical path of the at least one moveable optics; and 
 
 a controller configured to:
 control the actuator to position the at least one moveable optics towards a target position using the pulley system that is controlled according to a first set of control parameters when the at least one moveable optics is outside a threshold range of the target position; and 
 control the actuator to maintain the at least one moveable optics at the target position at steady state using the pulley system that is controlled according to a second set of control parameters when the moveable optics is within the threshold range of the target position.